Mold coating



Nov. 12, 1929. H. 5. LEE 1,735,120

MOLD comma Filed March 8, 1926 2 Sheets-Sheet l I N V EN TOR.

NOV. 12, 1929. 5, LEE

MOLD COATING Filed March 8, 1926 2 Sheets-Sheet Ill/1.-

7% INVENTOR. a?? \f? l e. BY Z I I ATTORNEY.

Patented Nov. 12, 1929 UNITED STATES HARRY S. LEE, OF PLYMOUTH, MICHIGAN MOLD COATING Application filed March 8, 1926. Serial No. 93,057.

This invention relates to methods for preparing permanent molds for casting, and the separation of the castings.

It has been common practice in molds to use a suitable parting material, and in permanent molds it has already been proposed to coat the mold cavity with a carbon deposit by sooting the mold surface with the lamp black furnished by an acetylene fiame.

I have discovered that a much more efficient and better way of preparing the mold is to spray a carbon solution upon the mold sections. It secures a much more even application of the parting material than can be attained by a flame deposit, which is subject to eccentricities which make a reliable deposit rather difficult to obtain.

Fig. 1 is a plan view of an improved apparatus for carrying out my method.

Fig. 2 is a vertical section on the line 22 of Fig. 1.

FFig. 3 is a section on the line 33 of Fig. 4 is a vertical section through the spraying apparatus and one of the mold sections.

Fig. 5 is a section on the line 55 of Fig. 4;.

Preferably a plurality of permanent molds designated A are carried on a revolving table 18 and are caused to open and close by automatic means. They are not detailed here for they are no part of the present invention. The point is, that while the molds are open, as shown in Fig. 1, where the mold sections are designated aa. The faces of'the mold cavities are automatically coated with a parting material. A pair of fan-like spray nozzles Z) are supported from a spray pipe 0, 40 which hangs from the fluid main (Z. This is guided and supported by a carrier .arm 6. The part of the table designated 7 rotates, the part designated 9 is stationary. In the center of the stationary table is the rotating 4 central table it which carries the arm 6, which is preferably counterweighted at 2'. A. stop is located on the rotating part of the table and the stops j are located on the mold guides, nd as they come along they nick up the carrier arm 6, as shown in Fig. 2, by engaging against the dependin arm la; this hooks the rotating table and t e carrier arm up together. Now refer to Fig. 3, the fluid main d rides up the see-saw m till it rides over the fulcrum and against the stop n. This elevates the carrier high enou h so that it carries it out of reach of the pic -up stop y. The see-saw, however, has its end caught in the notch 0 of the upright p and consequently it has become a horizontal track on which the fluid main 0? can ride back. However, the heavy tractile springs g bring the main (1 back with such a slap that they force the upright, which is carried on a spring arm out of engagement with the see-saw m; this per- 05 mits the main d, together with the supporting arm e to drop and to be again picked up by one of the pick-up stops 9'.

The above is simply an illustration of an automatic apparatus which has the function of suddenly dropping a pair of jets in between two mold sections; then causing the jets to travel along at the same speed as the traveling mold, and at the same time to gradually elevate to lift them out of the top of the mold, thereupon, a quick spring action causes the jets to be thrown back to the following pair of mold sections where they are precipitated to the bottom of the mold section and then caused to ride along with such mold sections then gradually rise. Various other apparatus for accomplishing this function could be designed, and conceivably the process could be carried out by hand, but obviously it could not be accurately and reliably done as is the case with machine aid.

I do not claim the apparatus in the pending application, as this has been claimed in my Patent No. 1,635,369, granted July 12, 1925, but I do claim the process, and partic- 0,0 ularly the particular process and composition thrown on the molds. 1

I prepare a spraying solution comprising lamp black mixed, or in solution, with a fluid, which is volatile under high temperaj tures. I find a solvent such as kerosene,

which is not volatile under ordinary temperatures, as very suitable for this purpose. Preferably, I mix with sufficient solvent onequarter graphite and three-quarters lamp black to get a solution thin enough to spray. The graphite, by reason of its greasy, pasty character tends to form an eflicient binder which binds the carbon together better than is the case of lamp black alone. However, very good results can be obtained with lamp black alone.

The action is to throw the parting fluid into the mold surfaces under pressure. This insures the mold cavity being evenly coated by the spray, as the spray cannot be diverted from its object as easily as a gas flame operated under such pressures as are permissible. The spray is very much less liable to become non-uniform by reason of stoppages in the orifices, etc. Furthermore, the spray when it strikes the mold face is fluid and is capable of some flowing action to unite the coating in uniformity before the great heat of the mold evaporates the solvent. Kerosene is not a normally volatile fluid, it is therefore very suitable for my purpose as it is a solvent of carbon and will remain on the mold face long enough to flow and even up the coating before it is volatilize'd by the heat of the mold face.

It is esential, of course, in spraying a fluid upon the face of the mold as a parting material that the coating be as uniform .in thickness throughout as is meghanically possible. It is therefore necessary to move the spray at a graduated speed upwardly, or downwardly, through the mold. This could, of course,-be performed by hand, but not with the precision and accuracy that can be accomplished by machine aid. I therefore emplog some such apparatus as I have describe What I claim is:

1. A preparation for coating mold faces at high heat, which comprises lamp black, graphite, and a liquid volatile only at high temperatures.

2. A preparation for coating permanent mold faces under heat, which comprises substantially one-quarter graphite and three quarters lamp black, carried in kerosene at a dilution that makes the substance capable of being sprayed.

In testimony whereof I have affixed my signature.

HARRY S. LEE.

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